Enantiomer-sensitive spectroscopy and mixture analysis of chiral molecules containing two stereogenic centers – Microwave three-wave mixing of menthone

We demonstrate three-wave mixing for enantiomer differentiation in the microwave regime using rotational transitions in cold gas-phase samples of menthone and carvone. The technique can also be understood as a polarization-dependent double-resonance experiment and has recently been shown to have high chiral sensitivity and mixture compatibility due to its resonant character. We here apply it to molecules containing two stereogenic centers, an important step towards investigating more complex species. We also demonstrate simultaneous microwave three-wave mixing of two structurally related monoterpenes, menthone and carvone, in a chiral mixture, which is possible due to the high sensitivity of rotational spectroscopy to structural differences